When I started weightlifting, I had trouble gaining muscle and lifting heavier weights. Eating more protein changed everything.

• I was running as my main form of exercise for years and not paying much attention to my diet.
• Once I started weightlifting, I realized I don't get nearly enough daily protein.
• Adding more salmon, eggs, tinned fish, and protein powder has made a huge difference to my fitness.

When I first started running in my mid-20s, I felt like I was the healthiest I'd ever been. I jogged a few miles every other day, not really paying attention to what I ate. If anything, I felt more emboldened to consume whatever I wanted because I was "burning it off" with exercise.

Over the years, I got more serious about running, joining a local group and finishing my first half-marathon. While I still could run the distances I wanted, I noticed I'd feel exhausted after, and couldn't keep up with other people very easily.

Still, I didn't think much of it because I felt fine. For years, I unknowingly followed the Mediterranean diet, cutting out red meat in favor of fish, eggs, whole grains, and vegetables. My annual blood tests were totally normal. And I was still working out regularly with no injuries.

But recently, I realized that I've been depriving my body of an essential nutrient for years.

I started weightlifting and struggled to make progress

Earlier this year, my friend found an introductory weightlifting class and we both decided to try it out of curiosity. We fell in love with the gym, both got annual memberships, and started going a few times a week.

While it got a little easier with practice, I would sometimes get lightheaded in the middle workouts and felt completely drained after deadlifting. I also struggled to go up in weight, always going for the lightest weights possible.

My friend used a protein calculator to figure out her ideal protein intake based on her height and weight and started eating more meat and supplementing with protein powder. I watched her quickly advance to heavier weights and look ripped as hell, so I realized it was time to examine my own diet.

Calculating a few days' worth of meals, I found out that I was only getting about 30 grams of protein a day — far less than the minimum recommended amount of protein for women, which is 46 grams (and more if you're actively working out).

Apparently, the berry-peanut butter-hemp seed-chia seed oatmeal I had every morning, that I assumed was a protein goldmine, was barely making a dent.

Simple tweaks made an enormous difference

I decided to get serious about adding more protein to my diet.

I didn't add any new foods to my already pescatarian diet, but I focused on incorporating more protein-rich staples. I started adding salmon and vegetables to my usual rotation of tofu stir-fries and lentil curries.

I also looked for quick high-protein snacks to have in a pinch. Tinned fish, eggs, and smoothies with plant-based protein powder all give me a little boost without much effort on my part. Sometimes I'll even add a scoop of protein powder to my coffee, which makes it sludgey and a little gross, but I'm a budding gym rat. This is my life now.

As a result, I generally snack less and feel full throughout the day. I also don't crash as much as I used to.

Gaining more muscle made me a better runner, too

Predictably, I started to see both immediate and long-term improvements in my weightlifting class. I could lift heavier and had more energy on days I ate more protein, and I started to notice slivers of visible thigh muscles after a few months. Plus, as someone with ADHD, I wasn't zoning out as much in class now that I was eating more protein and fatty fish.

But one of the best side effects was how much easier running got. Racing longer distances now, I can move faster without straining so much. I also recently hit a record speed for myself.

I plan to run a full marathon next year, and the idea of training already scares me! But with a better diet, at least I know I'll be putting my best, protein-fueled foot forward.